I tend to use airborne and aerosolized mostly interchangeably because the difference only matters in very specific discussion.

For the curious a disease is airborne when the individual bits of the disease (spores, cells, virus, etc) can travel through the air on its own. Something aerosolized gets airborne by traveling in some other airborne particulate like saliva or mucus. So the disease in SIS isn't actually airborne on its own, but it hangs around in the air in the aerosolized particles of breath or a sneeze. Clotho mentioned it to the commander because a filter might work for one but not the other.

One of those things that hovers in the background of the comics but which I doubt will ever come up in the story itself.